US2652611A - Separable slide fastener - Google Patents

Description

Sept. 22, 1953 JASTER 2,652,611

SEPARABLE SLIDE FASTENER Filed Dec. 28, 1950 W 510mg 4.44/4 1/ ATTORNEYS Patented Sept. 22, 1953 SEPARABLE SLIDE FASTENER Erich Hermann Ernst J aster, Eggenfelden, Nuderbayren, Germany Application December 28, 1950, Serial No. 203,129 In Germany January 2, 1950 7 Claims. (Cl. 24-201) The present invention relates to separable slide fasteners, and more particularly to slide fasteners comprising a pair of continuous grooved strips of semi-resilient material having a longitudinally uniform cross-sectional configuration which permits the strips to be pressed together into interlocking engagement with each other, or to be pulled apart at will.

Slide fasteners of this type are known, but the conventional forms of closure construction oifer inadequate resistance to pulling stresses in a direction transverse with respect to the grooved strips and tending to pull the strips apart, unless the closure strips are made of such a thickness that their field of utility is materially restricted.

Accordingly, it is among the objects of the invention to provide a slide fastener of this character which has a minimum thickness, but which nevertheless offers a satisfactory resistance to pull.

A further object of the invention is the provision of nove1 slider for use in coupling and separating these resilient grooved strip closure members.

Other objects and advantages of the invention will become apparent upon reading the following specification together with the accompanying drawing forming a part hereof;

Referring to the drawing:

1 is a transverse sectional view of a pair of resilient closure members which may be pressed together or pulled apart at will.

Fig. 2 is a longitudinal sectional view of an asymmetrical slider taken on a plane passing through the line 2-2 of Fig. 3, looking in the direction of the arrows.

Fig. 3 is a transverse sectional view of the slider shown in Fig. 2, taken along the line 33 of Fig. 2, looking in the direction of the arrows.

Fig. 4 is a transverse sectional view of the slider shown in Fig. 2, taken along the line 44 of Fig. 2, looking in the direction of the arrows.

Fig.5 is a longitudinal sectional view of a modified form of slider which is symmetrically shaped.

Fig. 6 is a plan sectional view of the slider shown in Fig. 5, taken along the line 6-6 of Fig. 5.

Referring now to the drawings in detail, in the fastener illustrated in Fig. 1, the closure portion consists of two identically shaped interlocked fastening strips.

These interlocked strips may conveniently be extruded from semi-resilient material which is sufficiently resilient to permit the fastening strips to be pressed together into interlocking engagement with each other, or to be pulled apart at will, and at the same time provide sufiicient rigidity to retain the fastening strips in the interlocked engagement with each other under conditions likely to be encountered when the fastener is in use.

The strips may be formed of a thermoplastic material such as a polymerization product of polyvinyl, styrene, acrylic acid ester, high polymer ethylene or the like.

The strips may have cross-sectional dimensions which are too small to be produced with accuracy by a conventional extrusion press, and where this condition is encountered, the extruded material may be drawn between rolls as it emerges from the press to obtain a uniform reduction of cross-section to the desired dimensions while the material is still in a plastic state. After the desired reduction in cross-section has been obtained, the material is hardened by cooling, either in air or by means of a liquid. In order to maintain uniformity of cross-sectional dimensions throughout the length of the strip, the drawing speed must be maintained at a constant fixed ratio with respect to the speed of extrusion.

These interlocking fastening strips comprise the thin laterally extending strips 1 and 2 terminating in the thickened outer beaded edge portions la and 2a, and the central portions 3 and 4, hereinafter called the coupling portions, which are offset with respect to the thin strips and 2 and formed integrally therewith. The outer surfaces of the coupling portions 3 and 4 are parallel to each other and to the laterally extending strips I and 2. On their oppositely disposed interengaging inner sides the coupling portions 3 and 4 are provided with a plurality of rib-like projections 5, 6 and l, 8 projecting toward each other from the coupling portions in a vertical direction and being so arranged on the coupling portions that longitudinally extending grooves are formed intermediate the ribs, the grooves having a cross-section whose configuration is substantially identical with that of l, 8. The cross-sectional shape of each rib is such as to terminate in a fiat outer end portion, with a laterally projecting hooking surface disposed intermediate the outer end and the root of the rib. The Width a of the hooking surface should not exceed half the root thickness b or the rib. A greater width of hooking surface increases the size of the outer end portions of the ribs and interferes with the pressing of the two fastening strips into interlocking engagement with each other. The outer lateral surfaces 6a and la of the outer ribs 6 and I are completely covered by the vertical inner surfaces of the central wall portions 3a and 4a of the fastening strips in such a way that the inner surfaces of the wall portions 3a and 4a bear snugly against the outer lateral surfaces 6a and la of the ribs and thereby prevent the ribs from becoming disengaged from each other when the strips are subjected to lateral stresses. The root thickness 22 of the ribs may be selected according to requirements and should be adequate to withstand the stresses to which the slide fastener is subjected. If the slide fastener is constructed in this manner, the pulling stresses encountered when the fastener is in use, and which tend to pull the fastening strips apart, will be effectively resisted by the interengaging ribs to 8. The height of the ribs should be kept to a minimum so that the overall thickness of the fastener will be as small as possible. This is particularly desirable where the fastener is embodied in an article of apparel. To prevent the formation of gaps between the outer lateral surfaces to and 7a of the ribs 6 and I and the inner surfaces of the central wall portions 3a and 4a, the thin laterally extending strips I and 2 may be joined to the coupling portions 3 and 4 closer to the outer surfaces thereof than shown and more nearly in alignment with the root portions of the ribs. The laterally extending beaded edge strips I and 2 are adapted to be secured by stitching or other convenient means to edge portions of a garment or other device with which the fastener is to be used.

A slider specially adapted for opening and closing the fastener shown in Fig. 1 is illustratively shown in Figs. 2 to 6. The slider may be formed of metal or other rigid material.

Fig. 2 illustrates an asymmetrical slider comprising a unitary casing 9 of generally S-shaped cross-sectional configuration provided on the entering side (indicated in the drawing by the arrows) with upper and lower walls 9a and 9b and with the partition II] positioned between the walls 9a and 9b. In this way the casing 9 has been subdivided at its entering side into the guide passages I l and I2, as illustrated in Fig. 3. Each of these guide passages is provided with a slot l3 or I4 extending longitudinally of the slider in the opposite side walls thereof. The slots I3 and I4 correspond in width to the thickness of the thin strip-portions I and 2, and the cross-section of the guide passages II and I2 corresponds to the cross-section of the coupling portions 3 and 4 provided with the ribs 5, 6 and I, 8. From the guide passages II and I2 the thin portions I and 2 of the strips project laterally outwardly through the slots I3 and I4. The passages II and I2 are shown provided with grooves (I5 and I6) and projecting ribs (I1 and I8) corre sponding in shape and number to the projecting ribs and grooves of the coupling portions of the fastening strips, and which are disposed in staggered relationship with respect to each other in such a manner that the grooves I5 of the upper guide passage are positioned directly above the projecting ribs I8 of the lower guide passage, while the grooves IB' of the lower guide passage are positioned underneath the projecting ribs I! of the upper guide passage. When the fastening strips are introduced into the slider on the entering side of the latter the ribs I and 8 of the upper coupling portion engage in the grooves I5 in the upper side of the partition I'D, while the ribs 5 and 6 of the lower coupling portion engage in the grooves I6 in the underside of the partition I0, whereby the hook-shaped sides of the ribs are compressed to such an extent that behind the rear end of the partition ID the ribs 5, 6 and I, 8 can easily slip into the oppositely disposed grooves between the ribs of the two strips. This interlocking engagement of the two strips is enforced by the construction of the slider which is so constructed that its upper and lower walls 9a and 9b conically converge towards each other behind the rear edge Ifla of the partition II).

In the form of construction illustrated in Fig. 2 the conical converging portion of the slider is asymmetrically tapered with respect to the partition I0, that is to say, the lower wall 9b is of rectilinear formation, while the upper wall 9a conically converges at toward the lower wall 9b until at the rear end of the conically converging portion 90 the interlocking of the two fastening strips has been completed. After this the two walls 9a and 9b extend parallel to each other to the rear end of the slider. The lateral slot I4 of the lower guide passage is straight throughout its entire length, while the slot I3 of the upper guide passage extends parallel to the upper wall 9a and 9a to the rear end of the slider where both of the slots I4 and [3 are positioned in the same plane (see Fig. 4) corresponding to the plane in which the two interlocked fastening strips are positioned (see Fig. 1.) The rib projections I1 and I8 on and beneath the partition I I] and consequently also the grooves intermediate these rib projections do not extend up to the front edge of the partition II), thereby facilitating the introduction of the fastening strips into the slider (see Figs. 2 and 5). On the other hand, at the rear end of the partition II) the rib projections I! and I8' extend somewhat beyond the rear edge of the partition. By reason of this latter fact and because the coupling portions 3 and 4 of the strips conically converge towards each other at this place (see Figs. 2 and 5) the introduction of the ribs 5, 6 and I, 8 into the corresponding grooves of the strips is considerably facilitated.

As will be seen from the cross-section shown in Fig. 3 the slider is of substantially S-shaped formation, so that the upper and lower walls are connected with each other only by the partition I0. In order to increase the rigidity of a construction of this kind, even with the partititon remaining comparatively thin, the upper wall (and if considered advisable also the lower wall) may be provided on its outer surface with reinforcing ribs I9, as illustrated in Figs. 3 and 4. Arranged between the reinforcing ribs I9 is the bail 20 provided with the finger-piece 2|, by means of which the slider can be shifted forwardly or backwardly depending on whether the slide fastener is to be closed or opened.

In the modification illustrated in Fig. 5 the construction of the slider corresponds substantially to that shown in Figs. 2 to 4. However, in this case both of the guide passages II and I2 as well as their lateral slots I3 and I4 are conically convergent toward each other behind the rear end of the partition in perfectly symmetrical fashion.

In both of the forms of construction shown in Figs. 2 to 4 and Fig. 5 the side walls of the slider extend parallel or substantially parallel to each other throughout its entire length. If desired. the guide passages III and Il may be provided with fan-like laterally enlarged portions, as shown in Fig. 6. This fan-like enlargement can be provided for each of the guide passages II and I2 only on a single side thereof. For the upper guide passage H the fan-like enlargement Ila has been provided at the side of the slot l3, while for the lower guide passage [4 the fanlike enlargement is disposed at the side of the slot H. The provision of these fan-like enlargements prevents undue constriction of the laterally separated disengaged portions of the fastening strips. But it is necessary in a construction like this to make the projecting guiding ribs on the upper and lower side of the partition of different lengths. These projecting guiding ribs I'm and Nb, in order to accommodate the fastening strip which enters the slider angularly displaced with respect to the longitudinal axis thereof, must be longer at the straight side of the passage than at the laterally flaring enlarged side of the passage (see Fig, 6). The degree of shortening of the projecting ribs depends upon the size and angular arrangement of the fan-like enlargements. Moreover, with the laterally flaring slider construction, the guiding ribs "a and Nb should not extend to the front edge of the partition In nor project beyond the rear edge lea of the partition as described above for the non-flaring embodiment shown in Fig. 3. For a flaring vertically symmetrical slider, as shown in Fig. 5, it is desirable to arrange the partition l with the guiding ribs on both its upper and lower surfaces extending rearwardly past its edge lfla. In the case of a flaring slider of vertically asymmetrical construction, as shown in Fig. 2, only the guiding ribs on the upper side of the partition ill need extend rearwardly beyond the partition edge Illa.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a separable slide fastener of the class described, in combination with a pair of uniformly shaped continuous coupling strips of semi-resilient material, each of said coupling strips consisting of a comparatively thin fastening portion, for fastening each strip to an edge portion of a device to be opened and closed by the fastener, and of a coupling portion formed integrally with said fastening portion, said coupling portion consisting of a continuous outer rib connected on one side to said fastening portion, said outer rib being fiat on its opposite free side, of a plurality of continuous coupling ribs of hook-shaped cross-sectional configuration on the side turned toward said outer rib and flat on the side turned away from said outer rib, and of a continuous backing strip having a fiat outer surface and from the inner side of which said outer rib and said plurality of coupling ribs project in parallel and spaced relationship, being so shaped that between said outer rib and said plurality of coupling ribs recesses are formed which correspond in cross-section substantially to the cross-section of said coupling ribs, so that when said pair of uniformly shaped coupling strips are interlocked said plurality of coupling ribs of one coupling strip engages snugly in the plurality of recesses of the cooperating coupling strip and vice versa, while said straight-lined free side of each of said outer ribs of said cooperating pairs of strips rests snugly against and covers said flat side of the outermost coupling rib of the cooperating coupling strip, whereby said flat outer surfaces of said backing strips extend parallel to each other and form in conjunction with said outer ribs a coupling body of substantially rectangular crosssection; the provision of a slider for interlocking and separating said pair of uniformly shaped coupling strips, consisting of a pair of superposed guiding chambers for said coupling portions of said pair of coupling strips separated from each other at the entering side of the slider by a partition and conically converging near the outlet end of the slider behind the rear end of said partition into one single guiding chamber of such restricted vertical depth that the coupling portions of said coupling strips when passing from said pair of superposed guiding chambers into said single guiding chamber are forced into interlocking coupling engagement with each other, said partition extending parallel to the interlocking plane of said coupling strips and being provided on its upper side and underside with a plurality of longitudinally extending rib-like projections corresponding in number to the number of recesses in said coupling portions and staggered with respect to each other in such a way that the rib-like projections on the upper side of said partition are positioned above the recesses between the rib-like projections on the underside of the partition so that the rib-like projections on the upper side of the partition when in engagement with the recesses of the upper coupling portion open up said recesses for said coupling ribs of the lower coupling portion positioned in the recesses between the rib-like projections on the underside of the partition and vice versa for mutual engagement when said coupling portions are forced into interlocking coupling engagement with each other behind the rear edge of said partition, said slider being further provided on either side with a longitudinally extending guiding slot suitably positioned for said fastening portions of said pair of coupling strips to project therethrough while said coupling portions are being guided within said guiding chambers, said guiding slots extending from the entering side to the outlet side of the slider in such a way that they converge behind the rear end of said partition into a common plane corresponding to the center plane of the interlocked coupling strips.

2. A separable slide fastener according to claim 1, in which said rib-like projections on the upper side and underside of said partition project beyond the rear end of said partition in somewhat conically converging fashion.

3. A slide fastener according to claim 1, in which the upper one of said pair of superimposed guiding chambers is provided with a fan-like enlargement at the side in which said longitudinally extending guiding slot is formed.

4. A slide fastener according to claim 1, in which both of said pair of superimposed guiding chambers are provided with fan-like enlargements at the sides in which said longitudinally extending guiding slots are formed.

5. A slide fastener according to claim 1, in which the upper one of said pair of superimposed guiding chambers is provided with a fanlike enlargement at the side in which said longitudinally extending guiding slot is formed, and in which said projections on the upper side of the partition are of different lengths and s0 arranged that those positioned nearest to said fanlike enlargement are farthest displaced toward the rear end of the partition.

6. A slide fastener according to claim 1, in which both of said pair of superimposed guiding chambers are provided with fan-like enlargements at the sides in which said longitudinally extending guiding slots are formed, and in which said rib-like projections on the upper side and underside of said partition are of difierent lengths and so arranged on the partition that 5 those positioned nearest to said fan-like enlargements are farthest displaced toward the rear end of the partition.

7. A slide fastener according to claim 1, in which said pair of superimposed guiding chambers are sonically convergent toward each other behind the rear end of said partition in asymmetrical fashion, and in which said rib-like pro- 8 iections on the upper side or said partition are projecting beyond the rear end of the partition.

ERICH HERMANN ERNST JASTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,480,027 Statham Jan. 8, 1924 1,959,318 Sundback May 15, 1934 2,294,555 Hendrie Sept. 1, 1942 2,303,870 Wahl Dec. 1, 1942 2,558,367 Madsen June 26, 1951

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